Stable indigo-white preparations and process of making same.



. ing by themselves.

UNITED STATES PATENT OFFlCE.

ALBRECHT SCHMIDT AND ADOLF STEINDOR'EF, OF HOCHST-ON-THE-MAIN, GERMANY,

ASSIGNORS TO FARBWERKE VORM. MEISTER- LUCIUS & BRT l'NING, 0F HOCHST-ON- THE-MAIN, GERMANY, A CORPORATION OF GERMANY.

' STABLE INDIGO-WHITE PREPARATIONS AND PROCESS OF MAKING SAME.

No Drawing.

To all whom it may concern:

Be it known that we, ALBRECHT ScHMIo'r, Ph. D., chemist, and ADOLF S'rnINpoRFF, Ph. D., chemist, citizens of the Empire ot Germany, residing at Hochst-on-the-Mam, Germany, have invented certain new and useful Improvements in Stable Indigo- \Vhite Preparations 'and Processes of Making Same, of which the following is a specification.

In U. S. Patent No. 906,307 is described a process of manufacturing stable concentrated indigowhite or indigo-white salt preparations, particularly suitable for the cold fermentation-vat, which comprises mixing indigo-white or an alkali salt ofmdlgowhite with molasses, syrup, saccharine substances or their technical equivalents, and

then, if necessary, concentrating or completely drying them by evaporation.

We have found that, instead of the abovementioned bodies, lactic acid preparations (under which term we comprise lactic acid, lactates, and the hereafter-mentioned substances containing lactic acid) may beadvantageously incorporated with the ind1gowhite or with its salts (both comprised under the term indigo-white preparations). The present process constitutes a technical improvement on that described in the above mentioned U. S. patent, in that when employing lactic acid or lactates, both of which yield aqueous syrupy solutions losing water with difiiculty, it is vpossible to use even smaller quantities than when using the bodies mentioned in said U. S. patent, which are soluble in water, of a syrupy consistency, of neutral reaction and capable of ferment- The lactic acid and the lactates do not ferment, therefore it is not necessary to employ so highly concentrated solutions of said bodies as is the case with carbohydrate solutions.

Example f: 50 kg. of indigo-white, in the form of a press-cake obtained by strong pressure, are kneaded with 80 kilos of lactic acid of 50% strength, and, if necessary, con centrated by evaporation in cacao. The preparation of indigo-white thus obtained,

containing 30% of indigo, forms a thin, syrupy liquid which can easlly be made 1nto a paste with water; even when allowed to stand for a prolonged time, it does not show any traces of fermentation or moldiness.

Specification of Letters Patent.

Application filed June 6, 1912. Serial No. 702,126.

Patented Feb. 25,1913.

Example 11: 25 kilos of indigo-white in the form of a 20% paste is mixed while stlrring with 10 kg. of lactic acid of 50 per cent. strength and 28 kilos of caustic soda lye of 40 B. specific gravity, and the mass 1s evaporated to dryness in 'vacuo. When dry, the product becomes friable and spongy; it readily dissolves in water and yields a brown vat. The stability of the preparation so obtained is excellent.

In the place of the lactates there may of course be employed technical preparations containing lactic acid, such as, for instance. the reactiomproducts containing lactates produced by the action of alkaline hydrates or carbonates, or alkaline-earth hydrates, (these three substances being comprised under the term alkaline agents upon glucose or other sugar substances or by reduction of indigo by means of glucose and an alkali hydrate. \Vhen using such substances, the indigo may be reduced by means of glucose and an alkali hydrate at a temperature which must not be too high and in a solution which must not be too concen trated, and then the solution is evaporated to dryness in' a vacuum. 1

The new preparations are gray to brown bodies, soluble in dilute alkalis, being precipitated from these solutions by means of dilute acids, and showing on the one hand the known reactions of the indigo-white and on the other hand those of the lactic acid.

Having now described our invention what we claim is:

1. The process of manufacturing stable concentrated preparations of indigo-white, particularly suitable for the fermentationvat, which consists in incorporating lactic acid preparations with preparations of indigo-white.

2. The process of manufacturing stable concentrated preparations of indigo-white,

particularly suitable for the fermentation- 3. The process of manufacturing stable concentrated preparations of indigo-white,

-particularly suitable for the fermentationvat, which consists in incorporating preparations containing lactic acid, formed by the action of alkaline agents upon saccharine LOO tions of the indigs-Whiie zmd. on the other substances, with preparatioms 02? incfigw hand those oi the lactlc aclrl white, and evaporating said J-repmaxtions tof dryness. In testlmony whereof "we our s1gmas new precincts, the harem described tux-es 1n presence 0f 3W0 wltnesses.

e 1 9 3; Y 13) w ALBRECHT SUE 1mm whlte pm'tlcularly 5111mm; L01 the -el'menta- T Tm I L ADOM): STEHWM Hon-vat, bemg gray w brown boches soluble 1n chlute mkahs, helng precaplmted from v Yhtnesses: these solutlons by means of dilute fields, and 1 JEAN GRUND,

10 showmg 0n the one hand the known reac- CARL GRUND. 

